<script lang="ts" setup name="XtxCarousel">
import {BannerItem} from '@/types/data'
import { onMounted, onUnmounted, ref } from 'vue';
// vue3的语法
// defineProps({
//   slides:{
//     type:Array,
//     required:true
//   }
// })

// vue3+ts语法
const {slides,autoplay=false,duration=3000} = defineProps<{
  slides: BannerItem[]
  autoplay?: boolean
  duration?: number
}>()

// 声明初始化值
let active = ref(0)

// 上一张与下一张
const prev = ()=>{
  active.value--
  if(active.value < 0){
    active.value = slides.length - 1
  }
}

const next = ()=>{
  active.value++
  if(active.value > slides.length - 1){
    active.value = 0
  }
}

// 当组件加载完毕时(挂载)开启自动轮播  TS认为setInterval是node中的setInterval
let timer = -1
onMounted(()=>{
  start()
})

// 当组件销毁时,关闭定时器
// vue2:descroyed()
onUnmounted(()=>{
  stop()
})

const stop =()=>{
  clearInterval(timer)
}

// 如果autoplay为false 不要开启setInterval
const start = () => {
  if(!autoplay) return
  timer = window.setInterval(()=>{
    next()
  },duration)
}
</script>

<template>
  <div class="xtx-carousel" @mouseenter="stop" @mouseleave="start">
    <!-- 轮播区域 显示 与 隐藏 是否有 fade类-->
    <ul class="carousel-body">
      <li 
        class="carousel-item" 
        :class="{fade:active===index}"
        v-for="(item,index) in slides" 
        :key="item.id"
      >
          <RouterLink to="/">
            <img
              :src="item.imgUrl"
              alt=""
            />
          </RouterLink>
      </li>
    </ul>
    <!-- 上一页 -->
    <a href="javascript:;" 
    class="carousel-btn prev"
    @click="prev"
      ><i class="iconfont icon-angle-left"></i
    ></a>
    <!-- 下一页 -->
    <a href="javascript:;" 
    class="carousel-btn next"
    @click="next"
      ><i class="iconfont icon-angle-right"></i
    ></a>
    <!-- 小圆点  active 高亮-->
    <div class="carousel-indicator">
      <span 
        :class="{active:active===index}" 
        v-for="(item,index) in slides" 
        :key="item.id"
        @click="active=index"
      ></span>
    </div>
  </div>
</template>

<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>